Back in 1964, movie audiences were treated to three hit musicals. Two of them — Mary Poppins and My Fair Lady — won scads of Oscars. But it was the third that announced the future, and it did so from its opening chord.

What followed from that chord was what we call The Sixties.

To celebrate the 50th anniversary of A Hard Day's Night, there's a spectacular new restoration that you can now see in theaters in its Janus Films release or buy on DVD and Blu-ray from the Criterion Collection. The black-and-white photography is so gorgeous, you'll swoon.

The movie is not half bad either. It was directed by Richard Lester, a filmmaker as underrated as he was influential. Lester took what was designed to be a promo film for the Beatles and — along with screenwriter Alun Owen — crammed it with ideas from the French New Wave and his own slapstick short, The Running Jumping and Standing Still Film, which is on the DVD. The result is a pop artifact that still crackles with freshness and energy. In Lester's verite, hyperkinetic approach to the musical sequences — and, boy, are the songs good — you'll find the template for a million later music videos.

The movie's title came from a malapropism by Ringo Starr that, in its paradoxical poetry, felt as inevitable as a folk saying. It fit perfectly a film that purported to capture a typical day in the life of the Beatles, who spend 87 minutes singing, clowning, hanging around a TV station, and, crucially, fleeing hysterical fans. You see, this isn't just a movie about rock stars but about rock stars playing themselves in a movie that's riffing on rock stardom.

Of course, even as the Beatlemaniacs sob and shriek, one of the movie's conceits is that people over 30 don't get it. On a train ride, the four are joined in a car by a stuffy, blimpish, mustachioed businessman who closes the window they've just opened and, when they turn on the radio, clicks it off.

Watching A Hard Day's Night today, our perceptions are shot through with historical awareness. The Beatles now seem astonishingly innocent in their neat suits and ties, and it's hard not to laugh at how the older characters harrumph at their long hair and cheekiness, for the boys are lovable mop tops — well-scrubbed, unprofane, decidedly nonthreatening. They're so spiffy that in these days of hip-hop and piercings, parents might be delighted to have such nice young men for their sons. Yet the harrumphers weren't wrong. As that businessman on the train grasped, the Beatles and their followers were taking over the cultural train.

A Hard Day's Night brims with Marx Brothers' irreverence, if not anarchy, and like the brothers, each Beatle has a clear persona. John's the barbed, ironical one who carries himself like a pop genius. Paul's the handsome nice guy you wouldn't guess was a pop genius. George is the dark horse, the quiet young one with secrets. And Ringo — the most popular back then — was the gentle, sad-eyed one. In hindsight, such personas almost predict their destinies. Even as Ringo is still having a laid-back good time into his 70s, Paul now revels in his living landmark status — he's now photographed hanging out with Warren Buffett. With his hit records, mysticism and humanitarian work, George would become the triumphant dark horse before dying, at 58, from cancer. As for John, if any of the Beatles was fated to be murdered, it was always him — he was the lightning rod.

But all this would come later. A few months before A Hard Day's Night opened, the Beatles had landed in an America shattered by the Kennedy assassination not even three months earlier, an America yearning for something alive and optimistic. The band was the ideal antidote to such grief, for the Beatles themselves had risen from an even longer, deeper darkness, the shabby funk of a postwar, post-imperial Britain with a calcified establishment, a frustrated working class, and little future to offer the young.

In the unmistakable alchemy of their sound — and in their authentic laughter as they run from shrieking fans during the film's opening credits — the Beatles embodied the hope and vitality the world was looking for then and still loves to this day. Like Louis Armstrong, they created music that, even when sad, is bursting with joy. All those hard days and nights paid off, for more than any band I can think of, they captured the yeah-yeah-yeah of happiness.